I start with a bottle of water, the 16 ounce one you get in cases of 24. I refill it at least 3 more times during the day to make sure I'm getting all my water. I try to space them out so that I have one right after each meal and one extra in the afternoon. I pretty much chugged it the first few days because I really haven't been drinking water in a while. I bought a brita water bottle yesterday but I don't like having to squeeze it to drink, although it does taste good and I won't be recycling as much plastic.